Notices

Hi there dr_frost_dk. Nice work once again.

I am an audio lover but i don't understand much about electric components.

5 years ago i modded my n-gage tm so that it could have stereo speakers, using the stereo signal from the headphone jack, and i had some sucess with that, except the fact that the volume was really low. At that time i knew that i needed some Amp for that but never found any. Thanks to you i think my search is finally over

But now i have other idea, this one related to N900. I have received 2 days ago 2 barebones (without the motherboard) of 2 clevos m570ru-u from a friend, and that laptop have an subwoofer plus 2 speakers.

My idea is to use one of that subwoofer plus the stereo system inbuilt on n900, but i don't know how to use both system's at the same time, since when i plug the jack on the n900, the internal speakers shut down, as normal.

So the amp would be only used to the subwoofer.

This is an extra but is there any way to put some external volume control on the subwoofer?

The only tecnical spec about the subwoofer that i found is this "1x Built-in Woofer 2W".

I want to ask you some advices about this idea, if it has some viability or not, since i love the current sound of the n900, but it lacks some bass

Thanks in advance and sorry for the bad english and the wall of text

You would need a low-pass filter also, if you can't do it with software.

IMHO laptop with subwoofer sounds ridiculous marketing scam

Isn't that built in in the subwoofer? (sorry for ignorance)
and if it isn't, is it hard to make it with software (i know i don't know how to do it )

BTW, i have just upload some photos of the sub to compare size.

http://www.megaupload.com/?d=W1X454C2

I must agreed with you that in the case of this laptop model the sub is indeed weak. I know because i have it, thats why my friend gave me those barebones for future repair, but there are some laptops where the subwoofer gives an extra sound experience.

It depends on what you call a subwoofer. Low-pass filter is typically in the amplifier module like this.

So if this sub don't have this ( very likely) isn't there any low-pass filters in small sizes that could be attached to that amplifier board?

Thanks for the answers .I have to go for now.

See you later

even though I will never do mods like this (my soldering skillz are null) - its awesome to see what some of you guys do

I am an audiophile somewhat - have a vacuum tube system with a maraantz cd player myself, but i wouldnt even think about what you guys are doing lol

http://www.beis.de/Elektronik/Filter/Filter.html

Nice idea with the sub, not going to go to sub freq tho

But an easy way if doing it will be to build a passive sub filter, can be done with few resistors & caps.

The sub will be an addon to you N900 right?, it looks to be to big to have in the N900 (mugen cover).

The dock i made gives more bass then stock N900, you could try the other speakers first with the small 2x3W amp.

of course to make an optimal system you need 2x amps, 1 for speakers 1 for sub, of course this amp cannot operate in bridge or parallel (i haven't tried).

That will do it. Even headphones jack work as before. Of course this is only scheme, You don't necessary need to place in-built speakers outside Red line is left speaker signal, green is right speaker signal, black is ground, and mixed colors cable is one cable with amplified-lowpassed signal from both channels.

Alternatively, You can use only one lowpass-filter, but then You need to place it AFTER amplifier. This way, you amplify all spectrum, then lowpass it - approach with first lowpassing, then amplifying resulted output gives better quality. Ho ever, with such subwoo and speakers, You'll probably don't even notice difference. Still, with both methods, You probably can break window's glasses in 100 meter diameter, on full volume

Placing adjustable resistor just before subwoo allow to calibrate bass volume - as built-in speakers aren't amplified (don't try it, amplifier will blow Your speakers, they're doing their best now), this is probably must-have if You decide to do it as on my scheme.

Thanks for the answers

As i said before, i don't understand much about electronics (building systems with resistors and that sort of things...just know that "this cable" goes "there" and stuff like that :/ ).

The subwoofer would be an add on, but i would like to use the n900 speakers, and i would not like to "toy" with them, because last time i toyed with them i blow up one of them (via software) so i know they are fragile.

My idea wasn't to make one stereo dock because for that i have a set of this speakers that do the job well done : http://www.caie.com.pt/loja/images/X_MINI_II_.jpg. I want to have the internal speakers as normal as they are and to have the subwoofer as an add-on to make the sound better.

I don't mind to use the 3.5 jack to achieve it but when i use it the internal speakers shut down, as normal. I used one way (described in this forum )to use the speakers and the jack at the same time but that was the cause that made my right speaker blow up.

I will make some costum external housing for the sub with some friends with acrylic.

What Estel said was what i made with the n-gage 5 years ago, except the filters and the amp lol. But is there any way to achive the same result without having to open the n900? I don't have problems openning it but it came from the repair shop 1 week ago (repaired usb port = happy n900 owner )and because of that i have 6 months of warranty and i don't want to loose them.

And more sugestions for the lowpass filters? are they cheap and small? and without it this subwoofer is just a normal speaker?

Thanks again